Masonry conservation
In the context of the work of the Scientific Committee, widespread conservation, consolidation and restoration work was undertaken on the ancient masonry of the Palace of Knossos. The masonry of Evans’s reconstruction was also conserved, since this was considered necessary for reasons of stability and also aesthetics; this reconstruction is irreversible for both practical and ethical reasons.
The basic consideration was that the Palace of Knossos, like any monument, is unique, so its poor preservation, damage or destruction are irreversible.
Generally, the damage to the monument is associated with external factors connected to the environmental conditions of the area and the history of the Palace, as well as to endogenous factors arising from the structure of the foundations and the characteristics of the building material themselves.
During the course of the work, it was observed that the Minoan masonry in most parts of the Palace was set, without foundations, on the marly limestone (kouskouras) or on Neolithic layers. The rescue work on the masonry conservation-restoration consisted mainly of consolidation of the masonry, floors, mortar and plaster. The materials themselves (poros stone, limestone, gypsum) presented problems, which were treated as part of the stone conservation project.
At the same time, areas were configured or filled in where necessary, retaining walls or low walls were built in order to level the ground and permit the comfortable circulation of visitors, and other areas were roped off to protect them as much as possible.
The masonry conservation-restoration work at the Palace of Knossos consisted of the following stages: first the cement mortar used in earlier interventions was removed, in order to conserve the mud-brick and stone Minoan walls; this mortar was, of course, incompatible with the ancient building materials. The joints were then cleaned, consolidated and filled with new, compatible material known as “Theran mortar”, whose ingredients include Theran soil, quarry sand and slaked lime.
The limits of Evans’s restoration or other, later interventions were precisely defined, particularly at the points where ancient masonry meets new. In order to clearly distinguish between the ancient parts and the reconstruction, both the pointing and the depth of the mortar were differentiated.
As regards the position of the wooden supporting beams of the Minoan masonry, the capping stones and the old mortar were removed, the beam sockets consolidated, and the surviving building materials preserved as far as possible.
This provided important information on the position and diameter of the vertical and transverse beams, the position of the lengthwise beam supporting the walls, etc.
